The account includes advertising duties for the Werther's Originals, Mingles and Bendicks of Mayfair brands. The incumbent, McCann Erickson, declined to repitch.
Bendicks, which is owned by August Storck KG, will now brief Isobel with creating through-the-line brand building campaigns.
Paul Houlding, the managing partner at Isobel, said: "We are looking forward to a long-term partnership with Bendicks and relishing the challenges of the brands."
Initiative, the company's media agency, is unaffected by the review.
McCann Erickson picked up the Bendicks brief in July 2004 after a three-way pitch against Soul and Unity, the incumbent.
The agency later picked up the Werther's account without a pitch. Its first work for the toffee brand was to update its image by replacing the grandfather and child with a more modern family.